This corded speakerphone with caller ID and call waiting is the perfect solution for small businesses in need of a phone with two line support. Power Failure mode insures calling capability during power failures. Includes three-party conferencing and a 100 name/number phonebook directory. Lines: 2 Telephone Type: Corded.ATTML17929. ML17929. At&t At&t ML17929 Two-Line Corded Speakerphone.